Responses of the upper middle atmosphere (60–110 km) to the stratwarms of the four pre-map winters (1978/9–1981/2)

The global developments of the four stratospheric events (～20–50 km) are described, using balloon, satellite and rocket data. Winds data for heights of 60–95 km, derived from L.F. drift (52°N, 15°E; Europe) and M.F. radar (52°N, 107°W; Canada), are then compared with the stratospheric data. There is clear evidence that the preliminary planetary waves often penetrate strongly to ～90 km, and that mean wind reversals also occur. However, there are dramatic differences between European and Canadian mesospheric responses.     

The giant planets and their satellites: Report on the Cospar Symposium,Ottawa, Canada,May 18–21, 1982

A $\text{Symposium on the Giant Planets and Their Satellites}$ was presented in conjunction with the Twenty-fourth Plenary Meeting of the Committee on Space Research. This paper summarizes the talks presented and places the remaining papers of this volume in context.     

Heavy ion action on yeast cells: inhibition of ribosomal-RNA synthesis, loss of colony forming ability and induction of mutants.

The action of heavy ions (Ar to U) accelerated to specific energies up to about 10 MeV/u (u=atomic mass unit) on different functions of yeast cells was studied. Ribosomal-RNA synthesis is inhibited according to a single-hit mechanism. Inactivation cross-sections were linearly related to the ratio of the squares of the effective charge Z* and the velocity of the ions. It is concluded from the analysis that the range of the most energetic delta-electrons is larger than previously assumed. There is no such dependence for survival and induction of mutants. In both cases cross-sections increase with the ion's specific-energy indicating an important contribution of long-range delta-electrons. The analysis shows that diploid yeast is not killed by a single-hit mechanism even by very heavy ions if the track width is too small. The relative importance of the penumbral region is even more pronounced with the more sensitive strains.     

WAMDII — A wide angle Michelson Doppler imaging interferometer for spacelab

A CCD imaging device has been designed which combines a spatial resolution of 0.1° with a spectral resolving power of 10⁵, sufficient to measure Doppler shifts and line widths of individual atmospheric emission lines. It will be flown aboard Spacelab and will be used to study neutral winds and temperatures as functions of height, latitude and time of day.     

The Resolution Performance of Range Estimators

The theoretical basis and methods of implementation of a moment algorithm for the range separation estimation of two closely spaced point targets are presented. Moment estimation and noise filtering techniques introduced here result in a considerable improvement over Baum's algorithm. The error bounds are established and it is shown that the spectral moment estimator exhibits optimum (zero bias, minimum variance) performance when the target separation normalized to the standard deviation of the Gaussian pulse is 2?1.5. Monte Carlo simulation is performed to verify the approximations made and to demonstrate the feasibility of the working models.     

Comparison of resonant topologies in high-voltage DC applications

Because of their tolerance of transformer nonidealities, resonant converters are considered to be well-suited to high-voltage applications. The series and parallel resonant topologies, as well as a newly discovered hybrid resonant topology are compared for high-voltage applications. Design criteria which incorporate transformer nonidealities are developed and used in the construction of high voltage prototypes for each topology. It is found that the parallel topology leads to the lowest peak switch current and the most ideal behavior     

The Magellan project

Magellan is one of the future space projects being studied by the European Space Agency. The aim is to provide high resolution (λ/Δλ ≥ 2.5 × 10⁴) spectra in the far and extreme UV (between 500 and 1550 Å) of faint galactic and extragalactic objects (V ≤ 16^m). The instrument consists of a mechanical collimator, a concave holographic grating and a bidimensional photon-counting detector. A low resolution mode (λ/Δλ ≥ 10³) will provide spectra of objects as faint as 18^m.5. Magellan is planned as an observatory, operated in real time, and allowing interaction with the observer.     

Structure of the Martian atmosphere from ε-Gem occultation observations

We have collected information about Martian atmospheric scale heights derived from observations of the occultation of ? Gem by Mars on April 8, 1976. The observations give data in the altitude range ～50 to 80 km. A rough, unweighted average of results so far available yields a temperature of ～165°K. Excursions of ～±40°K about this mean may be present as a function of both altitude and areographic coordinates.     

Comments on "Optimum Bandwidth of a Low-Pass Filter for Detection of a Pulse in Nonstationary Noise"

In a recent correspondence1 a calculation of the optimum bandwidth of a low-pass RC filter for the detection of a pulse signal in nonstationary noise was presented. The purpose of this correspondence is: 1) to point out additional references to the work which has been conducted in the stationary noise case, and 2) to present an interesting alternate derivation of the expected output noise power for the nonstationary noise case.     

Dissipation of temperature perturbations in the middle atmosphere

It is often observed that the stratospheric and mesospheric temperature structure undergoes transient disturbances from its averaged steady-state behavior. The causes may be traceable to gravity waves, planetary waves, solar proton and relativistic electron precipitation, etc. We examine the theoretical time behavior of the atmospheric temperature following the cessation of such heating phenomena as it relaxes toward its quiescent steady-state value. We also study the time-dependent response during a model stratospheric-warming/mesospheric-cooling event. In particular, we investigate the roles of eddy heat conduction, non-LTE cooling in the 15μm CO₂ band, and an ambient vertical wind, and their relative importance as they depend upon altitude and time, in modifying temperature changes in this region.